Stress Urinary Incontinence: Passive Pelvis Adaptation?

In this theoretical paper, the concepts of elasticity are applied to the whole of the pelvic anatomy. A certaindifference in elastic- ity between the two sides of the vaginal cap could be the root cause of the adaptation of vesicourethral and vaginal structures under stress. Under abdominal pressure, the significant posterior elasticityof pelvis allows the bottom and the back tilt of the an- terior wall of the horizontal vagina and its propulsion forward. The suspension of the anterior vaginal wall as a bridge suspen- sion propels the vaginal cap forwardand upwards in a pendulum mode. This movement allows the sliding backwards and down- wards of the bladder neck, and the creation of tension in the ver - tical suburethral vaginal wall by pulling it up and making it more rigid. The forward movement of the neck compresses the Retzius space, which increases the pressure therein. This increased pres- sure pushes back the only weak point of the walls of the Retz- ius space, the segment of the anterior vaginal wall located just above the pelvic diaphragm and pubourethral ligaments. This is followed by distal locking of middle urethra, the most effective mechanism of urinary continence under stress. On the whole, this theory assumes a totally passive adaptation of the urogeni- tal system under stress which is through mechanisms that trig- ger each other in a descending cascade. The active role of pelvic muscles would then be only a secondary one in strengthening this passive urogenital adaptation to stress.